•    OLIVE  SE5DK; 


loss- 


Bioletti,  Vj.F.   Oglesby  &  F.    . 

,    of  Calif.  Aerie.  ]Jxpt.  St.   Bui.  263 
•ch,    1916. 


feder 


UNIVERSITY  OF  CALIFORNIA 
AT   LQS  ANGELES 


UNIVERSITY  OF   CALIFOBMIA  PUBLICATIONS 

COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


GROWING    AND   GRAFTING 
OLIVE   SEEDLINGS 

PART  I.    GROWING  OLIVE  SEEDLINGS 

BY 

F.  T.  BIOLETTI  AND  W.  F.  OGLESBY 

PART  II.    GRAFTING  OLIVE  SEEDLINGS 

BY 
F.  T.  BIOLETTI  AND  F.  C.  H.  FLOSSFEDER 


BULLETIN  No.  268 

Berkeley,  Gal.,  March,  1916 


UNIVERSITY  OF  CALIFORNIA  PRESS 

BERKELEY 

1916 


306  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 

various  percentages  of  imperfect  seeds.  By  breaking  their  shells  and 
examining  the  kernels,  the  proportion  of  good  to  poor  was  determined 
for  a  number  of  samples  with  the  results  shown  in  Table  I. 

TABLE  I 
RATIOS  OF  GOOD  TO  POOR  SEED 

No.  of                                                                                                          No.  of           Good  seed,  Poor  seed, 

test                                                                                                               seeds             per  cent  per  cent 

1.  Pendulina;  Niles,  Alameda  Co 50               100.0  .0 

2.  Redding;  Davis,  Yolo  Co 100                99.0  1.0 

3.  Medium  sized  olives;  Tehama  Co 24                96.0  4.0 

4.  Small  sized  olives;  Tehama  Co 61                 91.8  8.2 

5.  Mission;  Davis  (1913),  Yolo  Co 38                 89.5  10.5 

6.  Picholine  d'Aix;  Niles,  Alameda  Co 36                 86.1  13.9 

7.  Mission;  Davis  (1914),  Yolo  Co 100                 86.0  14.0 

8.  Redding;  Fresno  709                 85.2  14.8 

9.  Rubra;  Niles,  Alameda  Co 40                85.0  15.0 

10.  Atro  Rubens;  Niles,  Alameda  Co 50                 80.0  20.0 

11.  Columella;  Niles,  Alameda  Co 100                 79.0  21.0 

12.  Polymorpha;  Niles,  Alameda  Co 50                 78.0  22.0 

13.  Oblonga;  Corning,  Tehama  Co 27                 74.0  26.0 

14.  Regalis;  Niles,  Alameda  Co 50                 66.0  34.0 

15.  Seedling;  University  Campus  550                 60.5  39.5 

16.  Razzo;  University  Campus  250                 54.0  46.0 

Percentage  of  good  seed:  Maximum,  100%.   Minimum,  54%.   Average,  81.9%. 


This  table  indicates  that  the  percentage  of  viable  seeds  differs  with 
the  variety,  with  the  locality  and  with  the  season.  Pendulina  from 
Niles  showed  100  per  cent  of  good  seed,  while  Regalis  from  the  same 
locality  showed  only  66  per  cent.  Redding  from  Davis  showed  99  per 
Cent,  while  the  same  variety  from  Fresno  showed  85.2  per  cent ;  Mission 
from  Davis  in  1913  showed  89.5  per  cent  and  in  1914,  86  per  cent.  The 
common  belief  that  the  seeds  of  the  Mission  contain  imperfect  kernels 
is  evidently  not  true  in  all  cases. 

In  order  to  obtain  a  true  comparison  in  the  germinating  tests  a 
method  was  sought  of  separating  the  good  seed  from  the  poor.  Such 
a  method  would  be  of  value  also  to  the  propagator,  as  it  would  enable 
him  to  avoid  the  useless  handling  of  worthless  seed.  As  the  good  seed 
is  of  higher  specific  gravity,  it  was  possible  to  separate  it  from  the 
poor  by  means  of  a  solution  of  common  salt.  The  good,  heavy  seed 
sank,  and  the  light,  worthless  seed  floated. 

It  is  necessary  that  the  salt  solution  be  of  the  proper  strength. 
If  too  strong  many  good  seeds  will  float  and  be  lost  and  if  too  dilute 
many  poor  seeds  will  sink  and  fail  to  be  eliminated.  The  proper 


GROWING  AND  GRAFTING  OLIVE  SEEDLINGS  307 

concentration  of  the  salt  solution  depends  on  the  condition  of  the 
pits.  If  the  pits  are  used  as  soon  as  they  are  cleaned  from  the  pulp, 
an  almost  perfect  separation  is  obtained  by  the  use  of  a  25  per  cent 
solution,  that  is,  a  brine  made  by  dissolving  25  parts  of  salt  in  100 
parts  of  water  by  weight.  If  the  pits  are  dried  for  several  weeks. 
a  10  per  cent  solution  gives  the  best  results.  If  the  dried  seeds  are 
soaked  in  water  for  two  days  they  can  be  separated  satisfactorily 
in  a  25  per  cent  solution.  If  soaked  for  a  long  time — fifteen  days 
— the  poor  seed  becomes  as  heavy  as  the  good  and  cannot  be 
separated.  The  seeds  of  a  few  varieties,  such  as  the  Mission,  with 
exceptionally  thick,  heavy  shells  require  a  still  more  concentrated 
solution.  Redding  seed  and  all  varieties  with  small  seeds  which  were 
tested  were  separated  well  in  a  25  per  cent  solution.  Table  II  shows 
the  results  obtained  in  separating  the  fresh  seed  of  various  varieties 
in  a  25  per  cent  brine. 

TABLE  II 
SEPARATION  OF  GOOD  SEED  FROM  POOR  IN  25  PER  CENT  BRINE 


No.  of 
test 

1.  Pendulina;  Niles  50 

2.  Redding;  Davis  50 

3.  Medium  sized  olive; 

Corning  24  96         23       *1         100           96 

4.  Small  olive;  Corning....       61  92  56       *1         ....         4         100          92 

5.  Pich.  d'Aix;  Niles 36  86         31       5         100         100 

6.  Rubra;  Niles 40  85  33       *1           1         5           94          94 

7.  Atro  Rubens;  Niles 50  80  40       *3         ....         7         100           93 

8.  Columella;  Niles 100  79  78       *2           1       19           99           98 

9.  Polymorpha;  Niles 50  78  39       *1         ....       10         100          98 

10.  Oblonga;  Corning 27  74  20       *2         ....         5         100          91 

11.  Regalis;  Niles 50  66  33       *2         ....       15         100          94 

12.  Seedling;  U.  C.  Campus     100  58  58       *8         ....       34         100           88 

13.  Razzo;.U.  C.  Campus  ....       50  54  27       *2         ....       21         100           93 
*Very  small  seed. 

Good  kernels  in  seed  before  separation 78.3% 

Good  kernels  in  seed  after  separation 95.7% 

Good  kernels  lost  in  separation  93% 

Poor  seed  eliminated 81.2% 


From  this  table  it  will  be  seen  that  before  separation,  an  average 
of  21.7  per  cent  of  all  the  seed  was  worthless.  After  separation,  of  the 
seed  recovered,  only  4.3  per  cent  was  poor.  Less  than  1  per  cent  of 


Per  cent 
No.  of       of 

No.  that 
sank 

No.  that 
floated 

Per  cent 
of  good 

Per  cent 
good  in 

seeds 

good 

,  ' 

>  , 

,  *• 

> 

seed 

seed 

used 

seeds 

Good 

Poor 

Good 

Poor 

retained 

retained 

50 

100 

47 

.... 

3 



94 

100 

50 

98 

49 

*1 

.... 

100 

98 

308  UNIVERSITY   OP    CALIFORNIA — EXPERIMENT   STATION 

the  good  seed  was  lost  and  over  80  per  cent  of  the  poor  seed  was 
eliminated. 

The  high  specific  gravity  of  the  few  bad  seeds  which  sank  was  due 
to  the  fact  that  they  were  solid  to  the  center  with  no  apparent  kernel 
cavity.  They  were  all  much  smaller  than  the  normal  seeds  and  would 
be  removed  by  screening.  Separation  by  immersion  in  brine,  followed 
by  removal  of  small  seeds  by  screening,  would  therefore  be  practically 
perfect. 

Most  of  the  germination  tests  were  made  with  Redding1  seed,  as 
this  variety  seems  particularly  suitable  for  a  stock.  The  percentage 
of  viable  seeds  was  high  in  all  cases  and  in  some  cases  there  was 
practically  no  bad  seed.  Where  seed  of  this  variety  is  used  the  main 
use  of  the  brine  test  would  be  to  determine  the  quality  of  the  seed  as 
a  whole,  in  order  to  decide  whether  the  sample  was  suitable  for  plant- 
ing, as  our  observations  indicate  that  where  a  large  percentage  are  not 
viable  even  those  which  germinate  produce  weak  plants. 

B.  PRELIMINARY  TREATMENT  OF  THE  SEED 

If  olive  seeds  are  planted  either  with  or  without  the  pulp  and 
without  treatment,  most  of  them  do  not  germinate  for  a  year  or  more. 
This  appears  to  be  due  to  the  oil  present  and  to  the  thick  woody  pit, 
which  delay  the  penetration  of  water,  without  which  the  seeds  cannot 
germinate. 

The  usual  method  of  handling  the  seeds  is  to  "stratify"  them  for 
about  sixteen  months  and  then  to  plant  either  in  "flats"  or  directly 
in  the  nursery.  Two  methods  of  stratification  are  used.  In  one,  the 
olives  are  mixed  with  sand  and  placed  in  a  box  or  pit.  They  are  kept 
moist  continuously  from  about  December  until  March  of  the  second 
spring  following,  when  they  are  planted  in  the  flats.  Another  method 
is  to  plant  the  seeds  about  an  inch  apart  in  a  box  or  bed  and  keep 
them  moist  until  they  germinate  and  grow  several  inches.  This  will 
take  nearly  two  years.  They  are  then  transplanted  to  flats  or  directly 
into  the  nursery.  There  is  a  loss  of  a  whole  year  in  each  case. 

Various  methods  have  been  recommended  for  hastening  the  germi- 
nation of  olive  seeds.  All  of  them  are  attempts  to  increase  the 
permeability  of  the  seed  to  water  by  removing  the  oil  or  by  softening 
or  breaking  the  stone.  Among  these  are  soaking  in  warm  water  or  in 
alkaline  or  acid  solutions,  feeding  the  olives  to  turkeys  and  using  them 
after  they  have  passed  through  the  digestive  tract,  and  cracking  the 
stones  in  a  vise. 


Usually  known  by  the  misleading  name  of  "Redding  Pieholine." 


GROWING    AND    GRAFTING   OLIVE    SEEDLINGS 


309 


Fig.  1. — Redding  olive  seeds  sprouting  in  a  large  box.  These  seeds  were 
stratified  by  the  first  method  in  December,  1912,  and  left  until  April,  1914, 
when  they  were  planted  in  the  box  shown.  The  photograph  was  taken 
twenty  months  after  the  seed  was  gathered. 


Fig.  2. — Redding  olive  seeds  sprouting  in  4-in.  flats.  These  seeds  were 
clipped  in  March,  1913,  and  planted  in  the  flats  as  shown.  The  photograph 
was  taken  in  August,  1913,  five  months  after  the  seeds  were  gathered, 
showing  a  gain  of  more  than  fifteen  months  over  the  stratifying  method. 


310  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

In  order  to  test  the  most  promising  of  these  methods,  several  series 
of  experiments  were  made.  In  the  first,  pits  of  a  small-fruited  seedling 
growing  in  the  University  grounds  were  used.  By  examination  it  was 
found  that  only  60.5  per  cent  of  the  pits  had  apparently  perfect 
kernels  (see  No.  15,  Table  I).  The  light  seed  was  removed  by  means 
of  a  25  per  cent  salt  solution,  the  proportion  of  good  seed  being  thus 
increased  to  88  per  cent  (see  No.  12,  Table  II).  The  experiments 
included  soaking  in  water  and  in  various  solutions.  Breaking  or  crack- 
ing the  shell  of  the  pit  by  means  of  a  vise  was  found  too  slow  and  by 
use  of  a  hammer  too  many  were  broken.  It  was  found  possible,  how 
ever,  to  cut  off  a  piece  of  the  shell  by  means  of  a  specially  designed 
pincer  rapidly  and  without  injury  to  the  seed.  Experiments  based  on 
this  method  were  also  included. 

The  seeds,  after  being  separated  in  the  salt  solution,  were  divided 
into  thirteen  lots  and  treated  as  indicated  in  Table  III. 

The  various  lots  were  all  planted  on  March  18,  1913,  directly  after 
treatment.  They  were  placed  in  the  greenhouse  in  shallow  boxes  con- 
taining a  mixture  of  three  parts  sand  and  one  part  garden  loam.  They 
were  put  in  about  half  an  inch  deep,  the  soil  firmed  and  kept  moist  at 
all  times.  The  germination  results  are  given  in  Table  III. 

TABLE  III 

EFFKCT  OP  PRELIMINARY  TREATMENT  OF  SEED  ON  GERMINATION 

Per  cent  sprouting  of 


No. 

Numi 

jer  sprouting 

~  ^ 

Good 

Seed 

Original 

No.  of 
test              Treatment 

used 

June  1 

July  1 

Aug.  16 

seed 

planted 

seed 

].  Soaked  and  apex  clipped 

250 

32 

98 

121 

55 

48 

29 

2.  Soaked  and  base  clipped 

250 

6 

59 

110 

50 

44 

27 

3.  Dry  seed,  apex  clipped.... 

125 

24 

46 

55 

50 

44 

27 

4.  Dry  seed,  notch  filed  

50 

1 

6 

18 

41 

36 

22 

5.  Dry  seed,  base  clipped  ... 

150 

12 

39 

40* 

30 

27 

16* 

6    1  hr  10%  HJ3O4       

200 

2 

23 

48 

27 

24 

15 

7    16  hrs    10%  KOH      

100 

0 

2 

21 

24 

21 

13 

8    Untreated  —  dry           

25Q 

4 

11 

45 

20 

18 

11 

9    Soaked  15  days             .  -- 

2075 

1 

62 

360 

19 

17 

10 

10.  30  min.  strong  H2SOt  .... 

200 

2 

13 

27 

15 

14 

8 

11.  42  hrs.  in  lime  paste  

50 

0 

0 

5 

11 

10 

6 

-i  o      Q   1,,.  .     1  {\crt    T?"f"\TT4t 

100 

1 

4 

f 

12.  a-ltrs.  lUyo  IS-wriT  

100 

0 

0 

13.  Pu^p  not  removed  

»  Some  of  the  seedlings  of  No.  5  were  lost  by  damping  off. 
f  Experiment  lost. 

These  results  indicate  that  not  only  was  there  a  large  proportion  of 
obviously  imperfect  seed  in  the  original  fruit,  but  that  even  the  separ- 
ated and  apparently  perfect  seed  had  low  germinating  power.  After 


GftOWWG    AND    GRAFTING   OLIVE    SEEDI.I  M,S 


Fig.  3. — Side  view  of  clipper. 

five  months  the  highest  per  cent  of  germination  obtained  was  29  per 
cent  of  the  original  seed,  48  per  cent  of  the  separated  seed,  and  55  per 
cent  of  that  which  appeared  to  be  perfect  on  inspection.  Later  tests 
indicate  that  the  seed  was  planted  too  deep  and  kept  too  wet.  The 
varying  percentages  of  germination,  however,  are  probably  a  fair 
measure  of  the  utility  of  the  various  methods  of  preliminary  treatment. 
They  indicate  that  soaking  in  water  for  fifteen  days,  in  10  per  cent 


Fig.  4. — End  view  of  clipper. 


312 


UNIVERSITY    OP    CALIFORNIA — EXPERIMENT    STATION 


sulfuric  acid  for  one  hour,  or  in  10  per  cent,  caustic  potash  for  sixteen 
hours,  does  little  or  no  good.  Soaking  in  strong  sulfuric  acid  for  thirty 
minutes  or  in  lime  paste  for  forty-two  hours  appears  to  be  injurious. 
Clipping  the  shell  of  the  pit,  on  the  other  hand,  increased  the  number 
of  seedlings  obtained  from  two  to  three  times. 


Fig.  5. — Redding  seeds  clipped. 

Another  series  of  experiments  was  made  with  Redding  seed  of  high 
germinating  power.  These  by  examination  showed  99  per  cent  of 
apparently  perfect  kernels.  After  separation  in  salt  solution,  the  pro- 
portion of  good  seed  was  practically  the  same.  Three  experiments  were 
made  as  follows: 

TABLE  IV 
EFFECT  OF  CLIPPING  SEED 

Number  sprouted 


No. 
used 


No.  of 
test          Treatment — March 

1.  Apex  clipped  250 

2.  Base  clipped  250 

3.  Untreated  ..  200 


May  1  June  1 
48 
24 

1 


July  1  Aug.  1 

166  221 

84  200 

17  60 


Per  cent 
sprouted 

88.4 
80.0 
30.0 


The  utility  of  clipping  the  seed  was  well  demonstrated  in  this  series. 

Seed  Clipper. — The  device  finally  adopted  for  clipping  the  seed  was 

made  from  a  pair  of  "farriers'  nippers,"  fourteen  inches  long  with  a 


GROWING    AND    GRAFTING    OLIVE   SEEDLINGS 


313 


a  6 

Fig.  6. — Germination  of  olive  seed  clipped  at  the  apex. 

one-inch  jaw.  This  was  mounted  on  a  board,  as  illustrated  in  figure  3. 
A  spring  between  the  handles  kept  the  jaws  open.  The  point  of  the  pit 
was  clipped  by  inserting  it  between  the  jaws  and  then  closing  them 
by  pressing  with  the  foot  on  a  wire  loop  attached  to  the  upper  handle. 
In  order  to  prevent  the  pit  being  inserted  too  far,  a  shield  consisting 


Fig.  7. — Stages  in  the  germination  and  growth  of  an  olive  seedling. 


314  UNIVERSITY   OP   CALIFORNIA — EXPERIMENT   STATION 

of  a  thin  piece  of  brass  was  rivetted  to  the  immovable  upper  jaw.  In 
this  shield  a  slot  was  cut  %2  °f  an  inch  wide  for  the  insertion  of  the 
pit.  To  prevent  cutting  the  kernel,  a  rounded  notch  was  filed  in  each 
jaw,  forming  when  closed  a  hole  %6  of  an  inch  in  diameter  vertically 
and  %6  horizontally.  This  hole  is  not  circular  as  it  appears  in  figure  4. 

This  clipper  is  suited  for  small  seeds,  such  as  those  of  the  Redding, 
which  seems  the  most  suitable  for  the  purpose  of  any  variety  available 
in  California. 

The  work  of  clipping  with  this  machine  is  easily  and  rapidly  done. 
From  1200  to  1500  seeds  per  hour  can  be  clipped  with  very  little  prac- 
tice. The  appearance  of  the  seeds  after  clipping  is  shown  in  figure  5. 

By  reference  to  Tables  III  and  IV  it  will  be  seen  that  a  somewhat 
larger  percentage  of  germination  was  obtained  where  the  apex  or 
pointed  end  was  clipped  than  where  the  clipping  was  done  at  the  base. 
The  superiority  in  rapidity  of  germination  is  even  more  marked  than 
the  total  number. 

The  probable  reason  of  this  superiority  is  shown  by  figure  6,  a  and 
b.  This  shows  that  the  radicle  or  germinating  point  of  the  seed  lies  at 
the  apical  end  and  that  when  the  shell  is  removed  from  this  end  it 
emerges  and  penetrates  immediately  into  the  soil.  When  the  base  is 
clipped  the  radicle  cannot  emerge  until  the  pit  splits.  Various  stages 
in  the  germination  and  growth  of  the  seedling  are  shown  in  figure  7. 

Treatment  with  Hot  Water. — The  germination  of  many  seeds  is 
facilitated  by  a  preliminary  immersion  in  hot  water.  The  effect  of 
this  treatment  on  olive  seed  is  shown  in  Table  V. 


TABLE  V 

EFFECT  OF  TREATMENT  WITH  HOT  WATER 

(100  Redding  seeds  from  Davis  in  each  test;  planted  Feb.  19,  1915) 

Number  sprouting 


test              Treatment 
1.  Soaked  48  hrs.  water 
2.  Soaked  *4  hr.  water 
3.  Soaked  1  hr.  water 
4.  Soaked  1  hr.  water 
5.  Soaked  ^4  hr.  water 
6.  Soaked  48  hrs.  wate 
7.  Untreated   . 

40°  C  

May  1 
0 

June  1 
10 
23 
17 
1 
24 
18 
17 

July  1     Aug.  16=total  % 
20                   32 
28                  35 
24                  30 
1                     1 
27                 44 
27                 43 
24                 40 

55°  C  

1 

55°  C  

15 

60°  C  

0 

60°  C  

6 

r    cold  

5 

1 

Soaking  for  one  hour  in  water  of  60°  C.  (140°  F.)  evidently  killed 
most  of  the  seed  (Test  4).  The  differences  between  the  final  results  of 
the  other  tests  and  of  the  untreated  seeds  are  slight  and  perhaps  within 


GROWING   AND    GRAFTING    OLIVE   SEEDLINGS  315 

the  limits  of  experimental  error.  Soaking  in  cold  water  for  two  days 
or  in  hot  water  for  a  short  time  apparently  hastens  germination.  This 
acceleration  of  germination  is  most  noticeable  in  No.  3,  where  the  seed 
was  soaked  for  one  hour  in  water  at  55°  C.  (131°  P.).  The  total 
germination  of  30  per  cent  compared  with  the  40  per  cent  of  untreated 
seed  indicates,  however,  that  some  of  the  seed  was  injured.  There  is 
no  evidence,  therefore,  that  water  treatment  is  of  any  value. 

Freezing  the  Seed. — Freezing  has  been  found  beneficial  in  hastening 
the  germination  of  some  hard  seeds,  such  as  those  of  peaches.  The 
effect  of  freezing  was,  therefore,  tested  with  olive  seeds.  Temperatures 
of  from  — 12°  C.  to  — 16°  C.  for  various  lengths  of  time  were  used. 
Some  of  the  seeds  were  immersed  in  water  during  freezing  and  some 
were  simply  wet.  The  pits  were  placed  in  small  metal-covered  cans 
and  immersed  in  a  freezing  mixture  composed  of  two  parts  of  broken 
ice  and  one  part  of  fine  table-salt. 

TABLE  VI 
EFFECT  OF  FREEZING 

(100  Redding  seeds  from  Davis  in  each  test;  planted  Feb.  19,  1915) 

Number  sprouting 


.wo. 

teal 
1 

OI 

t              Treatment 
In  water;  —  12°  C.  for  3  hrs. 

] 

tf  ay  1 
0 

June  1 
0 

July  1      Ai 
1 

ig.  1  6  =  total  % 
5 

9 

Wet;  —  12°  C.  for  3  hrs. 

0 

0 

3 

5 

3. 

In  water;   —12°  C.  to  —16° 
for  3  successive  days  

C.; 

1  hr. 

0 

0 

0 

0 

4. 

Wet;  —12°  C.  to  —16°  C.;  1 
successive  days 

hr. 

for  3 

0 

0 

0 

0 

5. 

In  water;  —  12°  C.  to  —  16° 
for  3  succesive  days 

C.; 

2  hrs. 

0 

0 

0 

0 

6. 

Wet;  —12°  C.  to  —16°  C.;  2 
successive  davs  ... 

hrs. 

for  3 

0 

0 

0 

0 

No  beneficial  results  were  obtained  in  any  case.  Three  successive 
freezings  killed  all  the  seed.  One  freezing  to  —12°  C.  (10.4°  F.)  killed 
most  of  the  seed.  The  effect  of  cold  on  dry  seeds  was  not  tested. 
Cooling  to  — 3°  C.  for  one  to  forty-eight  hours  had  no  perceptible 
effect,  but  the  tests  were  not  very  conclusive. 

C.  MOST  FAVORABLE  CONDITIONS  FOR  GERMINATION 

Successful  germination  depends  not  only  on  the  condition  of  the 

seed  when  planted,  but  on  the  environmental  conditions  after  planting. 

These  conditions  are  the  temperature,  the  moisture  and  the  aeration, 

for  each  of  which  there  is  probably  an  optimum.    Tests  were  made  to 


316  UNIVERSITY   OP    CALIFORNIA — EXPERIMENT   STATION 

determine  the  most  favorable  conditions  in  each  of  these  respects.  The 
seeds  used  were  Redding  from  Davis,  practically  100  per  cent  viable. 
The  pits  were  all  clipped  at  the  apex. 

Temperature. — For  this  test  the  pits  were  planted  in  six-inch  flower 
pots  painted  with  paraffin  to  conserve  the  moisture.  They  were  placed 
one-half  inch  deep  in  a  medium  light  sandy  soil.  Two  somewhat  con- 
stant temperatures,  that  of  the  office  regulated  by  a  steam  radiator, 
and  that  of  an  incubator  regulated  by  a  thermostat,  and  two  variable 
temperatures,  that  of  a  greenhouse  and  that  of  the  outside  air,  were 
tried.  The  results  are  shown  in  Table  VII. 


TABLE  VII 

EFFECT  OF  TEMPERATURE  ON  GERMINATION 
(55  Kedding  seeds  in  each  test;  planted  Feb.  22,  1915) 

Number  sprouting 

No.  of  / * x         Total 

test          Temperature  conditions  May  1      June  1      July  1      Aug.  16      per  cent 

1.  Outside,  mean  55°  F 0  23  29  29  53 

2.  Office,  mean  68°  F 0  33  34  35  64 

3.  Incubator,        mean  77°  F 00000 

4.  Greenhouse,     mean  80°  F 0  35  46  47  85 

(It  is  possible  that  the  seeds  in  the  incubator  may  have  become  too  dry.) 


Omitting  Test  No.  3,  it  is  plain  that  the  higher  the  temperature,  the 
more  rapid  the  germination.  The  outside  temperature  was  of  course 
variable  and  that  of  the  greenhouse  still  more  so.  In  the  latter  case 
the  temperature  on  a  sunny  day  often  exceeded  100°  F.  and  on  a  cold 
night  sometimes  fell  to  45°  F.  These  variations,  however,  seem  to  have 
had  no  effect  either  good  or  bad.  The  failure  of  the  seeds  at  77°  F. 
in  the  incubator  is  unexplained,  but  it  is  possible  that  they  were  allowed 
to  become  too  dry  at  some  time  after  starting. 

Moisture. — The  results  given  in  Table  VIII  under  this  heading  were 
the  result  of  an  accident,  but  are  none  the  less  suggestive.  Four  rows 
of  seed  were  planted  side  by  side  in  the  hot-house.  One  row  received 
the  ordinary  daily  sprinkling  only.  Another  was  kept  excessively  wet 
by  drip  from  an  overhanging  gutter.  A  third  received  a  portion  of  this 
drip  and  a  fourth  a  smaller  portion.  Four  increasing  amounts  of 
moisture  contents  are,  therefore,  represented  in  the  soil  of  the  four 
rows.  There  was  evidently  sufficient  moisture  in  the  row  receiving  the 
smallest  amount. 


GROWING   AND   GRAFTING   OLIVE   SEEDLINGS  317 

TABLE  VIII 

EFFECT  OF  VARYING  DEGREES  OF  MOISTURE  IN  SEED  BED 
(55  Redding  seed  in  each  test;  planted  March  24,  1915) 

Number  sprouting 

No.  of                                                                                      , >  Total 

test          Moisture  conditions  May  1     June  1  July  1  Aug.  1  per  cent 

1.  Received  drip  from  gutter 0           17  23  51 

2.  Received  less  drip  from  gutter 0           32  36  36  65 

3.  Received  still  less  drip  from  gutter  ....  0          40  46  46  84 

4.  Sprinkled  once  a  day,  no  drip 0           43  47  53  96 


The  deleterious  elTect  of  excessive  watering  is  plainly  shown  by 
these  tests.  The  injury  in  this  case  is  probably  indirect  and  due  to  the 
shutting  off  of  oxygen  by  preventing  proper  aeration.  It  is  probably 
of  the  same  character  as  that  shown  in  the  next  tests. 

Soil  Texture  and  Depth  of  Planting. — While  both  the  physical  and 
chemical  nature  of  the  soil  will  undoubtedly  affect  the  growth  of  the 
seedling  after  it  has  started,  it  seems  probable  that  the  germination  of 
the  seed  is  independent  of  the  chemical  nature.  The  effect  of  the  soil 
on  germination  depends  principally  on  the  way  in  which  it  affects  the 
temperature,  moisture  and  aeration.  The  tests  shown  in  Table  IX 
were  made  in  the  hot-house  and  the  moisture  received  was  sufficient  in 
all  cases.  The  differences  in  results  were  therefore  due  almost  or 
entirely  to  differences  in  aeration.  The  heavier  the  soil  and  the  deeper 
the  planting,  the  more  the  seed  was  removed  from  the  influence  of  the 
oxygen  of  the  air. 

TABLE  IX 
EFFECT  OF  SOIL  TEXTURE  AND  DEPTH  OF  PLANTING 

(Redding  seed) 

Number  sprouting 


No. 
test 

of 

Nature  of 
soil 
part  sand       

ueptn  ot 
planting 

lin. 

INO.  seea 
planted 

100 

jjaie  01 
planting 

Feb.  19 

Aug.  1 
44 

Per  cent 
44 

2. 

(2 

part  compost 
parts  sand  

J/>  in. 

55 

Feb.  22 

47 

85 

3. 

{' 

(4 

part  compost 
parts  sand 

%  in. 

55 

Mar.  24 

53 

96 

{' 

part  compost 

This  experiment  indicates  clearly  that  a  light,  open,  well-aerated 
soil  is  mast  favorable  to  germination.  It  also  indicates  that  the 
shallower  the  seed  is  planted  the  better,  providing  it  is  not  allowed  to 
become  too  dry. 


310 


UNIVERSITY  OP  CALIFORNIA — EXPERIMENT  STATION 


I 


Grafting  Stock. — There  is  nothing  in  these  experiments  to  indicate 
what  is  the  best  stock  on  which  to  graft  our  olives.  They  show,  how-1 
ever,  that  Redding  seedlings  have  many  of  the  characteristics  of  a  good 
grafting  stock,  and  grafted  trees  at  present  bearing  in  many  orchards 
show  that  they  have  others. 

Many  Redding  trees  are  scattered  all  over  the  state  and  the  variety 
is  fruitful.  This  makes  it  easy  to  procure  the  seed  in  any  desired 
quantities.  The  seed  is  small  and  of  very  high  germinating  power. 
The  growing  of  seedlings  is  therefore  simple.  The  seedlings  are  very 
uniform  in  size  and  character,  making  it  possible  to  obtain  grafted 
trees  of  even  size  and  rendering  it  probable  that  their  bearing  qualities1 


Fig.  8. — Redding  seedlings  on  right;  Algerian  on  left. 
Both  five  months  from  seed. 


will  also  be  uniform.  Finally,  the  seedlings  are  vigorous  and  readily 
take  the  graft  with  which  they  make  an  excellent  union. 

Incomplete  tests  have  been  made  with  other  stocks,  but  so  far  none 
of  them  has  shown  any  superiority  over  the  Redding. 

In  Europe  and  Africa  it  is  a  common  practice  to  plant  the  seed  of 
wild  olives,  or  to  use  wild  olive  seedlings  found  in  the  woods.  A  test 
was  made  with  some  seed  collected  by  Professor  R.  E.  Smith  from  a 
wild  olive  growing  in  Algeria.  At  first  it  promised  to  be  superior  to 
Redding  in  rapidity  of  growth.  The  seeds  were  very  small  and  germi- 
nated very  readily  and  the  seedlings  grew  vigorously  and  quickly. 
Figure  8  shows  the  relative  size  of  the  two  kinds  at  five  months. 


GROWING   AND   GRAFTING   OI,NE   SEEDLINGS 


319 


This  inferiority  of  size  of  the  Bedding,  however,  was  almost  over- 
come at  twenty  months  after  growing  six  months  in  the  nursery.    The 

' 


*  *fc  'VV'1        •*&< "TSuEV  ^  s 

4  W-.^mK^ 


Fig.  9.— Redding  seedling  to  right;  Algerian  on  left. 
Both  twenty  months  from  seed. 

low,  spreading,  bushy  form  of  the  Algerian  seedling  also  was  less 
suitable  for  nursery  work  than  the  tall  upright  growth  of  the  Bedding 
(see  fig.  9). 


320  UNIVERSITY   OP    CALIFORNIA — EXPERIMENT    STATION 


CONCLUSIONS 

These  results  make  it  possible  to  recommend  a  simple  and  rapid 
method  of  raising  Redding  seedlings  for  grafting  stock. 

1.  The  fruit  should  be  gathered  when  perfectly  ripe  and  the  pulp 
removed  from  the  pits.     This  is  most  easily  done  by  immersing  the 
olives  in  a  3  or  4  per  cent  soda  lye  for  several  hours  to  soften  the  skin. 
After  washing  off  the  lye,  the  pulp  can  be  removed  by  rubbing  through 
a  wire  sieve  of  %6-inch  mesh. 

2.  The  cleaned  seed  is  then  placed  in  25  per  cent  brine  (two  pounds 
common  salt  to  one  gallon  water),  and  all  floating  seed  rejected.2 

3.  The  apex  or  pointed  end  of  each  seed  is  then  clipped,  as  described. 

4.  The  clipped  seed  is  planted  directly  in  flats  containing  a  light 
porous  soil  (sand  three  parts,  leaf  mold  one  part).     The  seed  should 
be  planted  one-eighth  to  one-quarter  inch  deep  and  the  surface  of  the 
soil  covered  with  one-eighth  of  an   inch  of  sifted  moss  or  similar 
material. 

5.  The  planted  flats  should  then  be  placed  in  a  greenhouse,  cold- 
frame  or  ordinary  seed-bed,  and  watered  only  enough  to  prevent  com- 
plete drying  of  the  layer  around  the  seed.    The  warmer  they  are  kept, 
the  more  rapidly  the  seed  will  germinate  and  grow. 

6.  The  seedlings  will  commence  to  come  up  in  four  or  five  weeks  and 
continue  for  two,  three,  or  more  months.     At  the  end  of  about  five 
months  from  planting  they  may  all  be  transplanted  to  small  pots,  but 
they  will  be  of  many  sizes,  varying  from  a  few  inches  to  two  or  more 
feet  (see  figs.  10  and  11).    It  is  probably  best  to  pot  them  as  soon  as 
they  reach  four  or  five  inches,  as  in  figure  10.     This  will  necessitate 
going  over  the  seed-beds  several  times,  but  they  will  probably  make 
larger  trees  for  grafting  in  the  spring  than  if  they  are  set  back  by 
transplanting  when  large  as  in  figure  11. 

7.  The  potted  seedlings  are  kept  in  a  greenhouse,  lathhouse  or  other 
protected  place  until  the  following  spring.    When  the  weather  and  the 
soil  warm  up,  about  April,  they  can  be  planted  in  the  nursery  and  the 
following  autumn  and  the  next  spring  they  will  be  ready  for  budding 
or  grafting. 


2  Wash  seed  to  remove  salt  before  planting. 


GROWING    AND    GRAFTING   OLIVE    SEEDLINGS 


321 


Fig.  10. — Seedlings  potted  when  4  to  5  inches  high. 


I 


Fig.  11. — Seedlings  potted  when  1  to  2  feet  high  and  cut  back  to  6  to  8  inches. 


PART  II.-GRAFTING  OLIVE  SEEDLINGS 

By  FREDERIC  T.  BIOLETTI  AND  F.  C.  H.  FLOSSFEDER 


Qlive  seedlings  are  usually  budded  or  grafted  in  the  nursery.  This 
seems  to  be  the  best  way,  though  it  is  possible  to  plant  the  seedlings 
in  place  in  the  orchard  and  graft  them  one  or  more  years  later. 

Buds  may  be  put  in  during  the  autumn  to  unite  and  remain 
dormant  until  the  following  spring,  or  they  may  be  put  in  during  the 
spring  as  soon  as  the  sap  is  flowing  freely.  Spring  buds  grow  the  same 
year,  but  do  not  make  so  large  a  growth  during  the  season  as  those 
put  in  the  previous  autumn. 

.  Grafting  can  bejfone  in  almost  any  month,  but  the  best  time  seems 
to  be  just  at  the  start  of  new  growth,  a  little  before  the  time  for  spring 
budding,  usually  about  the  middle  of  March  in  most  localities.  . 

•  Some  growers  bud  their  nursery  plants  in  the  autumn  and  graft 
during  the  following  spring  all  on  which  the  buds  do  not ' '  take. ' '  This 
seems  to  be  a  good  method,  as  it  diminishes  the  number  of  failures. 
The  bud  is  inserted  four  to  six  inches  above  the  surface  of  the  ground 
and  the  grafting  is  done  at  or  just  above  the  surface. 

Neither  budding  nor  grafting  are  very  difficult  if  good  scions  are 
used.  The  graft  scions  or  bud  sticks  should  be  as  fresh  as  possible. 
If  kept  for  even  a  few  weeks  they  do  not  grow  nearly  so  readily.  They 
should  have  well  formed  buds.  Twig  buds  can  be  used,  but  more  of 
them  fail ;  the  ordinary  shield  bud  in  a  T  slit  is  the  simplest  form  and 
seems  as  good  as  any.  For  grafting,  a  method  by  which  the  stock  is 
not  split  seems  to  be  the  best.  The  bark  or  crown  graft  is  the  form 
usually  employed.  The  scions  should  be  not  only  fresh,  but  well 
developed  and  at  least  three-sixteenths  of  an  inch  in  diameter ;  about 
one-quarter  of  an  inch  is  perhaps  the  best  size.  If  over  three-eighths  of 
an  inch  they  are  difficult  to  fit  properly. 

GRAFTING  EXPERIMENTS 

In  order  to  determine  the  best  method  of  tying,  waxing  and  cover- 
ing nursery  grafts  a  series  of  tests  was  made  at  Davis  in  1915. 

Nursery  Grafting.— The  stock  used  in  these  tests  were  well-grown 
Redding  seedlings  similar  to  that  shown  in  figure  12.  They  were  just 

[322] 


GROWING   AND    GRAFTING   OLIVE    SEEDLINGS 


323 


two  years  old  from  the  planting  of  the  seed  and  varied  in  diameter 
at  the  base  from  three-eights  to  five-eights  inches. 


Fig.  12. — Bedding  seedlings,  two  years  old. 
Seed  planted,        March,  1913 
Plant  potted,         August  1913 
Put  in  nursery,     May,  1914 
Grafted,  March,  1915 


324 


UNIVERSITY    OF   CALIFORNIA — EXPERIMENT    STATION 


The  scions  were  taken  from  old  Mission  trees  growing  on  the 
University  Farm.  The  kind  of  scion  and  method  of  cutting  are  shown 
in  figure  13.  They  were  of  good  quality  with  well-formed  dormant  buds 


Fig.  13. — Mission  scions — slightly  reduced. 

and  somewhat  smaller  than  the  stock,  from  one-eighth  to  four-eighths 
inches  in  diameter. 

The  method  of  grafting  was  that  usualty  called  bark  or  crown 
grafting  and  consists  of  inserting  a  scion,  cut  to  a  long  single  bevel, 
underneath  the  split  bark  of  the  stock,  which  has  previously  been  cut 


GROWING    AND    GRAFTING   OLIVE    SEEDLINGS 


325 


Fig.  14. — Method  of  grafting  olive  seedlings  in  nursery. 
1.  Stock  decapitated.  2.  Bark  split.  3.  Scion  inserted. 

4.  Graft  tied.  5.  Graft  covered  with  moist  soil. 


326  UNIVERSITY   OP   CALIFORNIA — EXPERIMENT   STATION 

off  an  inch  or  so  above  the  surface  of  the  ground.  The  method  is 
shown  in  figure  14.  The  209  grafts  made  were  treated  in  three  different 
ways  as  follows: 

Exp.  1.  Tied  with  raffia,  waxed,  and  covered  with  soil  to  just  above  the  union. 
Exp.  2.  Tied  with  raffia,  waxed  and  covered  with  soil  to  the  top  of  the  scion. 
Exp.  3.  Tied  with  cotton  string,  no  wax,  covered  with  soil  to  the  top  of  the  scion. 

The  grafting  was  done  on  March  19,  and  on  July  1  the  results  were 
noted  as  follows : 

Exp.  1.  20  strong  grafts,  6  weakly.  Good  grafts,  24.7% 
Exp.  2.  44  strong  grafts,  6  weakly.  Good  grafts,  54.3% 
Exp.  3.  36  strong  grafts,  5  weakly.  Good  grafts,  76.6% 

From  this  it  appears  that  for  the  conditions  of  the  test  the  follow- 
ing conclusions  may  be  drawn : 

1.  Deep  covering  of  the  graft  with  moist  soil  is  necessary.    Compare 
Experiments  1  and  2. 

2.  When  the  grafts  are  covered  deeply,   waxing  is  detrimental. 
Compare  Experiments  2  and  3. 


UNIVERSITY  of  CALU<  ot 
LOS  ANGELES 


Syracuse,  N.  Y. 
PAT.  JAN.  21,1908 


A     001  055  286     7 


Of  CALIFORNIA  LIBRARY 
Los  Angeles 


ow. 


315 


326 

off  an  ir 
shown  in 
ways  as 

Exp.  1. 
Exp.  2. 
Exp.  3. 

The 
noted  as 


Froi 
ing  con 

1.  I 
Experii 

2.  \ 
Compai 


University  of  California 

SOUTHERN  REGIONAL  LIBRARY  FACILITY 

405  Hilgard  Avenue,  Los  Angeles,  CA  90024-1388 

Return  this  material  to  the  library 

from  which  it  was  borrowed. 


lethod  is 
different 

the  union, 
the  scion. 
:  the  scion. 

mlts  were 


he  follow- 

Compare 

trimental. 


UNIVERSITY 


LOS  ANGELES 


Makers 

Syracuse,  N,  Y. 
PAT.  JAN.  21,  1908 


A     001  055  286     7 


OF  CALIFORNIA  LIBRARY 
Los  Angeles 


315 


